Method of and apparatus for testing metals and alloys



M. A. MILLER July 14, 1931.

METHOD OF AND APPARATUS FOR TESTING METALS AND ALLOYS 3 Sheet-Sheet 1 92 9 l 5 m a J d I e lll July 14, 1931. M. A. MILLER 1,814,522

METHOD OF AND APPARATUS FOR TESTING METALS AND ALLOYS Filed Jan. 5, 1929I5 Sheets-Sheet 2 gwvamboz flax 4 #111 July 14, 1931. A M, MILLER1,814,522

METHOD OF AND APPARATUS FOR TESTING METALS AND ALLOYS Filed Jan. 1929 3Sheets-Sheet 3 Patented July 14, 1931 V UNITED STATES PATENT OFFICE MAXA. MILLER, OF NEW YORK, N. Y., ASSIGNOR TO MILWELL ELECTRIC DEVICESCORPORATION, OF NEW YORK, N. Y.

METHOD OF AND APPARATUS FOR TESTING METALS AND ALLOYS Application filedJanuary 5, 1929. Serial No. 330,564.

This invention relates to methods of and apparatus for testing metals,based upon their magnetic characteristics or the lack of it, and moreparticularly the invention refers to a method for testing nickel coinswhereby spurious and counterfeit coins can be easily detected andisolated from the others.

' Slot machines and automatic vending machines generally, which arerendered operative by the insertion of a nickel or similar coin are notproof as a rule against the insertion of slugs of a size and weightapproximately corresponding to those of a genuine coin.

As a result, the owners of vending machines and slot operated devicesare frequently victimized in this respect by unscrupulous users andtheir earnings are thereby reduced a material extent.

It is therefore desirable to provide devices and machines of thecharacter specified, with means for the automatic selection of the coinsinserted, said means being of a nature to pre vent the operation of themachine or device when a spurious coin or a counterfeit or foreign coinis inserted.

According to the present invention an automatic selection of the coinsmay be had by basing the operation of the selective devices employedupon the magnetic characteristics of the metal out of which a genuinecoin is made. For instance, I have found that a United States nickel isless susceptible to magnetic attraction than a Canadian nickel becausethe percentage of nickel in the alloy used for the production of UnitedStates nickels is smaller. For the same reason, spurious coinscontaining a material amount of iron are also more responsive tomagnetic action than a genuine United States nickel while other coinstotally made of brass or pewter or other non-metallic metal or alloy,respond to magnetic action in a still different way.

I have therefore developed a simple and reliable method of detectingspurious and counterfeit nickels which lends itself to be applied inpractical form to the operation of vending and slot machines generally.However, since this method of detection is based as stated, upon certainphysical characteristics of the metals or alloys out of which variouscoins and slugs may be made, it may be stated broadly that the inventionrelates in reality to a method for testing metals based on a newprinciple, that is, the utilization of the magnetic characteristics ofeach metal as compared wth a standard to be predetermined in advance.

The primary object of this invention is to provlde a simple and novelmethod of detecting and separating spurious and counterfeit coins, aswell as foreign nickels from genuine United States nickel coins.

Another object of the invention is to provide an apparatus embodying themethod mentioned, said apparatus being simple and reliable enough towarrant its practical application in slotand vending machines of anywell known type.

A further object of the invention is, broadly, to provide a method fortesting metals and alloys according to their magnetic properties, ascompared to those possessed by a standard of predetermined and knowncomposition.

Other objects and advantages of the present invention will more fullyappear as the description proceeds and will be set forth and claimed inthe appended claims.

As stated in the premises, my invention is based upon the fact thatmetals or alloys containing a greater or lesser amount of mag neticmaterial are attracted by a given magnet with a greater or lesserintensity. In the course of my experiments I have found that not onlynon-magnetic metals and alloys were not attracted by a magnet but thatthey were actually repulsed to a more or less degree. This led me tofurther experimenting, and as a result I have perfected a method ofisolating spurious and foreign nickels from genuine United States nickelcoins to a point Where it is susceptible of many practical applications.

My invention is illustrated in the accompanying drawings in a more orless systematic form, said drawings being intended by way of example andnot in a limiting sense, to assist in understanding the fundamentalfeatures of my invention.

Referring to said drawings Fig. l is a diagrammatic plan view of adevice embodying a method of magnetic detection which may be used forseparating counterfeit and foreign nickel coins from United Statescoins;

Fig. 2 .is another plan view of the same showing the operation of thedevice when a United States nickel coin is used;

Fig. 3 is a diagrammatic front elevation of a device in which not onlythe attraction or the lack'of it exertedby a magnet upon a metal oralloy is used, but also the repulsion exerted upon nonmagnetic metals oral- 10 s;

Fig. 4 is a plan view thereof, partly sectionedto show the arrangementof the coin passages;

Fig. 5 is a side sectional view of the same through line 5-5 of Fig. 4;

Fig. 6 is a side sectional view of the same through line 66 of Fig. 4:;

Fig. 7 is a detail front elevation of the magnet employed for therejection of nonmetallic coins; and.

Fig. 8 is a fragmentary side elevation partly sectioned of a devicesimilar to that illustrated in Figs. 3 to 7 illustrating the possibility of adjusting the magnetic action-by varying the distancebetween the magnet and a. COlIl.

The device illustrated in Figs. 1 and 2, is based upon the fact that ifa mass of pure nickel or a suitable alloy containing a fnagnetic metalis placed opposite the poles of a horse-shoe magnet and is spacedtherefrom a certain distance if a disk of metal or alloy is interposedbetween the magnet and the magnetic metal, the latter will be attractedonly if the metal or alloy thus inserted contains a certain amount ofmagnetic material while if no magnetic material is present the metaldisk will act as an effective shield preventing any magnetic action fromtaking place.

In other words, the'device is based upon the magnetic permeability ofthe metal which is being tested. Referring to Figs. 1 and 2, 10designates a horse-shoe magnet formed with two poles 11, 12 the endfaces of which 11, 12 are in line with the inner wall 13 of a coinpassage 14.

A piece of metal bar 15 made of nickel or some alloy containing magneticmaterial, having a cross section about equivalent to that of an ordinarynickel coin is placed endwise opposite poles 11, 12 of the magnet, andis spaced therefrom a distance somewhat 'greater than the thickness ofan ordinar nickel coin.

Said metal bar is provided with an arm 16 pivotally mounted at 17permitting the magnet to attract said bar against the action of asensitive retaining spring 18. Said bar is normallyretained by saidspring against a stop 19, and its angular displacements towards themagnet is preferably limited by another stop 20, allowing for aclearance to remain between the bar and the poles of the magnetsuificient for the passage of a nickel com.

Arm 16 has a rear extension 21 shown in dotted lines which is formedwith an upwardly projecting lu 22 normally blocking passage 14' beyondthe magnet; however, a slight angular displacement of arm 16 and bar 15towards the magnet is sufficient to move lug 22 to one side of thepassage as shown in Fig. 2. c When a spurious coin made of brass oraluminum or zinc alloy, etc., is run through passage 14-. up to andbetween the magnet and the bar, the bar being in the meantime held inits outer position shown in Fig. 1 by the spring, no action whateverwill take place upon the bar and therefore the progress of the coin willbe stopped by lug 22. If a genuine United States coin is insertedinstead, a slight attraction will take place, sufiicient to move lug 22to one side as shown in Fig. 2.

However, the attraction is solely exerted upon bar 15 due to themagnetic permeability of the coin, but the coin itself contains solittle nickel that the magnet will not attract it sufiiciently to stopits progress; therefore, the coin can continue on its way past lug 23 asshown in Fig. 2.

On the other hand, if a metal disk or a coin containing a largerpercentage of nickel such as for instance, a Canadian nickel isinserted, the same will be attracted by the magnet and held. If themetal disk or slug is made of iron, the magnetic action will be sostrong that a material force must be exerted in order to remove it.

It is obvious therefore, that a United States nickel will freely passbeyond the magnet and advance towards the mechanism controlling thevending or coin operated device as shown at 23 in Fig. 2; a spuriouscoin made of nonmagnetic material will remain loose between the magnetand the metal bar; a Canadian nickel or other coin containing a similaramount of nickel will lightly stick to the poles of the magnet and if aniron counterfeit is inserted it will stick to the magnet fast enough torequire some sort of mechanical action to detach it thereform.

It is obvious that iron counterfeit coins could also be stopped by aseparate magnet before they reach the position between magnet 10 and bar15. The magnet can be a permanent magnet or an electromagnet and must beplaced in the proper position with respect to metal bar 15 if it is todiscriminate properly between genuine coins and counterfeit coins. Thisposition depends upon the size, shape and magnetic properties of the bar15 and the magnet 10 and can easily be determined by actual test.

'As previously stated, I have found that when a counterfeit coin made ofaluminum, brass or other alloys not containing nickel or any othermagnetic metal is placed before a magnet the same will be repulsed bythe magnet and caused to tilt away therefrom.

By taking advantage of this action which I believe I am the first tohave discovered, I have devised a simpler and more effective method ofdetection of counterfeit coins which is embodied in the device shown inFigs. 3 to 7. In the same designates a coin chute at the outer end ofwhich a coin such as 32 can be inserted. Said chute is mounted on astand 33 and is slightly inclined downwardly in its intermediary portion34 ending with a downwardly directed tract 35, provided with a dischargeoutlet 36.

Two magnets 37, 38 which may either be permanent, or electromagnets asshown, are placed in succession at one side of the intermediary tract 34of the chute. The core 39 of the first magnet is spaced from the innerwall 41 sufficient to accommodate a coin between said core and said wall40, while the end of the core 42 of the second magnet is flush with theinner surface of wall 40.

An opening such as 43 is provided through wall 40 opposite magnet 37,said opening being large enough to permit the passage of a nickel coinin a transversal sense, and reaching to the bottom of the chute as shown1n Figs. 3, 5.

Another opening 44 is provided through the other wall 45 of the chutedirectly opposite magnet 38, and a discharge tube 46 displaced incorrespondence of said opemng, said tube extending away from the magnetand downwardly as at 47 and being provided with a discharge outlet 48.

Another chute 49 is provided underneath space 41 for the discharge ofthe coins which may reach said space by the action of magnet 37;furthermore, a rectangular tubular member 50 is provided above space 41,said member extending in an upward direction and acting as a guide for apiston 51 which is shown in its upward position and which may be causedto reciprocate so as to force a 00m from space 41 into chute 49. Themeans for operating this piston are not shown but it will be understoodthat any suitable well known mechanism may be employed to this end.

The operation of the device is as follows :If a genuine United Statesnickel coin is inserted through opening 31, the same will run by andbeyond opening 43 and W111 also continue in the same direction and passbeyond core 42 of magnet 38 ultimately reaching front 35 of thedlscharge outlet 36.

If a coin made of copper, aluminum, zinc, brass or pewter or some otheralloy free of any magnetic metal, is inserted through the chute it willpass by and beyond opemng 43,

but as it reaches the space in front of core 42, it will be more or lessviolently repulsed directly into discharge tube 46.

If on the other hand, a counterfeit coin containing a large amount ofiron, or else a foreign coin containing a larger percentage of nickelthan the United States nickel coin, is used, when the same on its wa thedischarge end of chute 30 reac es a positlon otpposite core 39 of magnet37, the action 0 said magnet will be powerful enough to attract saidcoin and force it sidewise through opening 43, causing the coin to stickto the end of core 39. The attracted coin itself may be used as will beunderstood to close a circuit or to otherwise start the operation of themechanism employed to operate piston 51 so that upon a coin being soattracted by core 39, the piston will move downwardly and force the coinbeyond said core and within chute 49 from whence it will be dischargedinto a suitable receiver,

By way of example, Figs. 3, 4 and 5 show two terminals 52, 53 of anelectric circuit represented by two wires 54, 55 which are shortcircuited by a coin when it is attracted by core 39. The electriccircuit which be-- comes thus energized may cause the operation ofpiston 51 in any suitable manner as will be understood.

I have found in practice that the repelling action of magnet 38 isintensified if a shading coil 56 is placed in front of the magnet so asto shield its upper half as shown in Fig. 7.

I have also found that the action of the repelling magnet isparticularly effective, reliable and efficient when the distance betweenthe bottom of passage 34 and the center of core 42 is greater than theradius of the coin 57 as Fig. 6 clearly shows, this being presumably dueto the fact that the greater the distance between the core and the loweredge of the coin, the greater the leverage.

While in the course of this description, I have mentioned dischargeoutlets 36, 48 and opening 31, it will be understood that these variousopenings may lead to any other passage such as may be required for theoperation of the machine onto which the device is applied.

As stated in the premises, the inventive idea may also be applied forthe testing of metals and alloys generally, fdr instance, for thepurpose of determining the amount of a given magnetic metal thereincontained. For this purpose, it may be desirable to vary the distancebetween a passage or conduit towards.

through which a metal disk may run, and the 7 as to be movable to andfrom'passage 59 by means of an adjust-ing screw 60 as will beunderstood.

By means of a device of this type, it is therefore possible to determineby comparison the relative magnetic attraction or repulsion exerted bythe magnet upon disks made of ditt'erent metals or alloys and similarlyit is also possible to determine the magnetic properties of such metalsand alloys in relation to a given standard.

It will be observed that the intensity of the magnetic action is notonly a function of the magnetic flux generated by the magnet, but isalso a function of the distance between the core of the magnet and thepiece of metal or alloy tested.

It is therefore obvious that although I have described a preferredarrangement where the second magnet practically exerts no attractionwhatever upon United States nickels, it is quite possible to conceive ofan arrangement where said magnet may generate a magnetic flux strongenough to attract these coins, preventing their being discharged throughthe end discharge passage, the pieces being subsequently detached bysome mechanical means such as described in connection with the firstmagnet. It is alsoconceivable that such pieces may pass beyond the firstmagnet by so regulating the magnetic flux generated thereby and thedistance from the passage that only pieces containing a higher amount ofmagnetic metal will be attracted.

The invention accordingly embraces in a generic sense the use of amagnet or magnets for the separation of metals or alloys containingdifferent amount of magnetic material and for the further separation ofmetals or alloys containing no magnetic metal whatever.

No attempt has been made towards illustrating in detail various Ways inwhich the invention can be applied. It is obvious that devices ofvarious designs can be produced embodying the inventive idea in waysdifiterent from those shown and described; however, since the methoditself is believed to be, broadly new, all such devices and arrangementsare held to fall within the scope of the present invention.

I accordingly reserve myself the right to carry my invention intopractice in all those ways and manners which may enter, fairly, into thescope of the appended claims.

I claim:

1. In 'a device of the class described, the combination with alongitudinal passage through which metal disks may be made to travel, ofa magnet transversely arranged at one side thereof, said magnet beingregulated to exert practically no action upon disks containing apredetermined amount of magnetic metal, and to repel disks made ofdiamagnetic metal, an opening through one of the amount of magneticmaterial, and means for detaching from said magnet, the disks thusattracted.

2. In a device of the class described, the combination with alongitudinal passage through which metal disks may be made to travel, ofa magnet transversely arranged at one side thereof, said magnet beingregulated to exert practically no action upon disks containing apredetermined amount of magnetic metal, and to repel disks made ofdiamagnetic metal, an opening through one of the sides of said passagelocated at a point nearer to the point of insertion of said disks,another magnet placed in cooperative relation to said opening, adaptedto attract through said opening disks containing a relatively highamount of magnetic material, and means for shifting disks thus attractedtransversely of said magnet in order to detach them therefrom.

3. In a device of the class described, the combination with alongitudinal passage through which metal disks may be made to travel, ofa magnet transversely arranged at one side thereof, said magnet beingregulated to exert practically no action upon disks containing apredetermined amount of magnetic metal, and to repel disks made ofdiamagnetic metal, an opening through one of the sides of said passagelocated at a point nearer to the point of insertion of said disks,another magnet placed in cooperative relation to said opening, andspaced therefrom, adapted to attract through said opening diskscontaining a relatively high amount of magnetic material, a dischargepassage in correspondence of the space between said second mentionedmagnet and said opening, and means for forcing disks attracted by saidmagnet into said discharge passage.

4. In a device of the class described, the

combination with a longitudinal passage through which metal disks may bemade to travel, of a magnet transversely arranged at one side thereof,said magnet being regulated to exert practically no action upon disksc0ntaining a predetermined amount of magnetic metal, and to repel disksmade of diamagnetic metal, a discharge passage beyond said magnet, anadditional transversal discharge pas sage opposite said magnet, anopening through one of the sides of said passage located at a pointnearer to the point of insertion of said'disks, another magnet placed incooperative relation to said opening, adapted to attract through saidopening disks containing a relatively high amount of magnetic material,and means for detaching from said magnet, the disks thus attracted.

5. In a device of the class described, the combination with alongitudinal passage through which metal disks may be made to travel, ofa magnet transversely arranged at one side thereof, said magnet beingregulated to exert practically no action upon disks containing apredetermined amount of magnetic metal, and to repel disks made ofdiamagnetic metal, a discharge passage beyond said magnet, an outwardlydirected transversal discharge passage opposite said magnet, an open- Iing through one of the sides of said passage located at a point inadvance of said magnet, another magnet placed in cooperative rela tionto said opening, and spaced therefrom, adapted to attract through saidopening disks containing a relatively high amount of magnetic material,a discharge passage in correspondence of the space between said secondmentioned magnet and said opening, and means for forcing disks attractedby said magnet into said discharge passage.

6. In a device of the class described, the combination with alongitudinal passage through which metal disks may be made to travel, ofa magnet transversely arranged at one side thereof, said magnet beingregulated to exert practically no action upon disks containing apredetermined amount of magnetic metal, and to repel disks made ofdiamagnetic metal, an opening through one of the sides of said passagelocated at a point nearer to the point of insertion of said disks,another magnet placed in cooperative relation to said opening, adaptedto attract through said opening disks containing a relatively highamount of magnetic material, and means for detaching from said magnet,the disks thus attracted, said means being controlled by said disks.

7-. In a device of the class described, the combination with alongitudinal passage through which metal disks may be made to travel, ofa magnet transversely arranged at one side thereof, said magnet beingregulated to exert practically no action upon disks containing apredetermined amount of magnetic metal, and to repel disks made ofdiamagnetic metal, an opening through one of the sides of said passagelocated at a point nearer to the point of insertion of said disks,another magnet placed in cooperative relation to said opening, adaptedto attract throu h said opening disks containing a relative y highamount of magnetic material, means for detaching from said magnet, thedisks thus attracted, and an electric circuit controlling said means,adapted to become energized by the action of said disks.

8. In a device of the class described, the combination with alongitudinal passage through which metal disks may be made to travel, anopening through one of the sides 9. In a device of the class described,the

combination with a longitudinal passage through which metal disks may bemade to travel, an opening through one of the sides of said passage, anda magnet placed opposite said opening adapted to attract through saidopening disks containing a relatively high amount of magnetic material,of an ejecting member adapted to detach from said magnet the disks thusattracted, and a normally open electric circuit controlling saidejecting member, said circuit being completed through one of said diskswhen thus attracted and becoming then operative to actuate said ejectingmember.

10. In a device of the class described, the combination with alongitudinal passage through which metal disks may be made to travel, ofan electromagnet transversely arranged at one side thereof, saidelectromagnet being regulated to exert practically no action upon diskscontaining a predetermined amount of magnetic metal, and to repel disksmade of diamagnetic metal, a discharge passage beyond said magnet, anoutwardly directed transversal discharge passage opposite said magnet,and a shading coil placed in front of said magnet so as to shield itsupper half portion.

11. In a device of the class described, the combination with alongitudinal passage through which metal disks may bemade to travel, ofan electromagnet transversely arranged at one side thereof, saidelectromagnet being regulated to exert practically no action upon diskscontaining a predetermined amount of magnetic metal, and to repel disksmade of diamagnetic metal, a discharge passage beyond said magnet, anoutwardly directed transversal discharge passage opposite said magnet,and a shading coil placed in front of said magnet so as to shield itsupper half portion, the distance between the bottom of said longitudinalpassage and the axis of said magnet being greater than the radius ofsaid disks.

MAX A. MILLER.

